*** Mon Oct 14 19:42:42 EEST 2002 - Dan

Double buffering
----------------

To avoid flickering caused by redrawing the widgets on Expose events, a
double buffering tehnique was implemented for most of the widgets.
This flickering effect has gotten more vizible with the introduction
of antialiased fonts. If with normal text one can redraw the text over the
old one over and over again without any degradation of the text (new pixels
simply overwrite old pixels), with antialiased text the situation is
different and text gets quickly corrupted. To avoid this corruption, one
needs to first erase the area where the text will go, which can cause the
before mentioned flickering.
The double buffer is implemented to solve this issue.

This is a change that that will be automatically available for any WINGs
applications and will require no change in the existing code.
However there is an exception from this in case of WMList if you delegate
the drawing of items to userspace (read below for the compelte details).


*** Mon Oct 14 22:07:42 EEST 2002 - Dan

WMList change
-------------

In case of WMList there is the posibility to delegate the drawing of the
list items to the application that is linked with WINGs, and this code will
not be inside the WINGs library, but in userland. Since we use the double
buffering tehnique in this case too (to allow all widgets based on WMList
and the ones that draw their list items by themselves to benefit from the
double buffering advantage automatically), we no longer pass the window to
the user code doing item drawing, but instead pass this pixmap in which we
draw before copying to the real window.

Since one cannot use XClearWindow() or XClearArea() on pixmaps, but only on
windows, if the code drawing list items used to call these functions to clear
the item area before drawing it needs to change to using XFillRectangle()
instead.

With this change it also means that there is no longer any need to do any
double buffering in the user code, since it's already done by WINGs.


*** Mon Oct 14 19:28:35 EEST 2002 - Dan

API change
----------

WMDrawString() and WMDrawImageString() no longer take a GC as argument.
Instead WMDrawString() takes a WMColor* as the color for the string to be
drawn, while WMDrawImageString() takes 2 WMColor* arguments in place of the
old GC: first for text color and second for background color.

This change is required to support extending WMFont to allow it to handle
antialiased fonts through the XFree86 Xft2 extension.

This also has the advantage of hiding low level X11 details and use WINGs
internat objects instead.

To fix your old code to work with the new WINGs API you need to replace the
GC passed to WMDraw***String() in your code with a WMColor*.
Most of the old code used to be like this:

WMDrawString(screen, window, WMColorGC(color), font, x, y, txt, len);

for the new API it should be replaced by:

WMDrawString(screen, window, color, font, x, y, txt, len);

However if you used a particular GC created by yourself to suit your special
needs, you need to pass a color which is the same as the foreground color of
that gc.

For WMDrawImageString(), from:

WMDrawImageString(screen, window, gc, font, x, y, txt, len);

becomes

WMDrawImageString(screen, window, textColor, backColor, font, x, y, txt, len);

where textColor and backColor are declared like:

WMColor *textColor, *backColor;

and have the color of the foreground respective the background of the old gc.



*** Wed Oct  9 07:10:04 EEST 2002 - Dan

Antialiased font support
------------------------

With the addition of Xft2 support in the WINGs library, now WINGs can display
antialiased text with TrueType or any scalable fonts.

Antialiased text is enabled by default, but can be disabled by adding

AntialiasedText = NO; in ~/GNUstep/Defaults/WMGLOBAL

This will disable antialiased text for any WINGs based application. If you
only want to disable them for a specific application only, like WindowMaker
for example, then add the same option in the applications configuration file,
in this case ~/GNUstep/Defaults/WindowMaker

Note that bitmapped fonts look much better than TrueType when antialiasing is
disabled.


*** Mon Sep 09 06:58:30 EEST 2002 - Dan

New delegate for the WMConnection class
---------------------------------------

ConnectionDelegate structure has a new member: canResumeSending.
The purpose of this callback is to notify you that you can resume sending
data over a WMConnection.
It works in the following manner:

WMSendConnectionData() can return 3 values: -1, 0, 1

-1 - means that the connection has died. you should stop sending data and
     close the connection ASAP.
 1 - means that the data was succesfully sent
 0 - means that the data (or part of it) was not sent. however, it was saved
     in a queue and the library will try to send it later when possible.

if the return value is 1, you can continue to send the next message, and so
on, until the return value of such a send call will be 0.
After it returns 0 you can continue sending, however, the data will not be
sent over the connection because the operating system cannot accept any more
data for the moment. Instead it will be queued inside the library, making your
program's memory footprint increase. If the ammount of data you need to
send is limited and not too big, this shouldn't be a problem, because your
data will be queued and sent when the operating system will notify the
library that sending is possible again.
If this is the case you can just ignore the output of WMSendConnectionData()
and not set a callback for canResumeSending.

However, if the ammount of data you have to send is undetermined and you
also want to keep a small memory footprint for your program (so that it
won't grow until it uses all your available memory ;) ), you will have to
stop sending data over the connection as soon as WMSendConnectionData()
returns with 0. Then you should somehow mark this situation in your program
to avoid it trying to send anymore data until notified that it can resume.
(You should have also set a canResumeSending callback when you initialized
your WMConnection object because else you cannot be notified when to resume.)

Now, when you receive such a 0 from the send operation, your last sent data
is put in a queue inside the library. At a later time when the operating
system notifies the library that sending is possible again, the library will
resume to send the data that is saved in the queue. After it will be able to
send all the data in the queue, the canResumeSending callback will be
called, letting you know that not only you can resume sending because the
operating system is again able to send data, but also that the queue was
completely flushed.

From the canResumeSending callback, you should again update the status of
your program marking that it can send again, and then resume sending the
data from where you were left.


*** Thu Oct 04 06:00:09 EEST 2001 -Dan

Property lists handling code
----------------------------

Code to handle property lists was added to WINGs. It is more robust
than the libPropList code, mostly because some conflicting concepts 
borrowed from UserDefaults (which libPropList use) are no longer used in
the WINGs property lists code. These borrowed concepts conflicted with the
retain/release mechanism of property lists and could lead in certain cases
to segmentation faults when executing libPropList based code. But the worse
part was that these libPropList problems were practically unsolvable without
removing one of those conflicting concepts and without a complete redesign. 
The new WINGs property lists code is also better integrated with the other
data types from WINGs and is actively maintained.

Practically the things that were removed from the WINGs property list
implementation compared to the old libPropList implementation, are exactly
the UserDefaults borrowed concepts that conflict with the retain/release
mechanism:
- The container of a proplist object and the associated functions are gone.
- The filename associated with a proplist object and the corresponding
  functions are gone. Now the saving function needs the filename as a
  parameter.
- The synchronization functions are no longer supported. They are part of
  the UserDefaults and are implemented there.
- No functions related to domains/registering were implemented in the WINGs
  property lists code, because they are also not part of property lists.
  They are more in connection with UserDefaults and a central point of access
  for domains.

The above 2 concepts: container and filename were added to libPropList just
to let it support synchronization which was borrowed from UserDefaults.
Property lists as defined in the openstep specification are just complex
data structures composed of strings, data, arrays, dictionaries and a mix of
them and are not associated with any file in particular. UserDefaults on the
other hand are property lists read from a specific file and they associate
that property list with that file and allow them to be synchronized.

Old libPropList based code can still be used by linking against the WINGs
library containing the new proplist code with minimal changes which are
described in detail in the comments at the top of the WINGs/proplist-compat.h
header file (the same file carries the #defines for mapping old libPropList
functions to the new WINGs proplist functions).
Our recommendation is to move to the new functions WINGs provide because
they better integrate with other function naming conventions in WINGs.
The proplist-compat.h header file is just a way to have old code up and
running with minimal changes so that we can remove the old and unmaintained
libPropList from systems while keeping to use old libPropList based code
without rewriting it and it should not be used for other purposes.


*** Sat Apr 21 09:12:09 EEST 2001 -Dan

API change
----------

To allow a correct display of icon images with alpha blending in panels and
other places where a WINGs based application may use them the following
changes took place:

1. The following functions were renamed:
   - WMSetApplicationIconImage()  --> WMSetApplicationIconPixmap()
   - WMGetApplicationIconImage()  --> WMGetApplicationIconPixmap()
   - WMSetWindowMiniwindowImage() --> WMSetWindowMiniwindowPixmap()
2. The following functions were added:
   - WMSetApplicationIconImage(WMScreen *scr, RImage *image)
   - RImage* WMGetApplicationIconImage(WMScreen *scr)
   - WMPixmap* WMCreateApplicationIconBlendedPixmap(WMScreen *scr, RColor *col)

As you can see the old functions that operated on WMPixmap images (which are
basically X Pixmaps that lack alpha information) were renamed to ...Pixmap()
to make them more suggestive about what they do and to make room for the
new functions that operate on RImages (that hold alpha information).

Since the corresponding WMGet... functions only retrieve the stored
image/pixmap from the application, I'll outline how the WMSet...
functions operate:

All WM...IconPixmap() functions operate on WMPixmaps
All WM...IconImage() functions operate on RImages


- WMSetApplicationIconImage() will set the RImage to be used in panels
    and will also convert the RImage to a WMPixmap with a threshold of 128
    and will use that pixmap for the appicon image. If that doesn't satisfy
    you, you can make a call to WMSetApplicationIconPixmap() on your own to
    set whatever WMPixmap you see fit for the appicon. 

- WMSetApplicationIconPixmap() will set the WMPixmap to be used for the
    appicon and for the panels 


If you use only one of the above functions, the corresponding image/pixmap
will be used everywhere where needed (panels and appicon), but the pixmap
version will not be able to handle alpha blending correctly.

If you use both WMSetApplicationIconImage() and WMSetApplicationIconPixmap()
then the RImage will have priority in panels, and the WMPixmap will only be
used for the appicon. This allows you to better control what icon is
displayed in the appicon, in case the default conversion of the RImage to a
pixmap with a threshold of 128 is not good enough, or in case you want a
different icon to be shown in the appicon than in panels.


Also this new function was added:

- WMCreateApplicationIconBlendedPixmap() will use the RImage set with
    WMSetApplicationIconImage() if available and will blend it with the color
    you passed. This will make the image show well on a background of that
    color. If the RImage was not set it will return NULL. You need to call
    WMReleasePixmap() on it after you finish with it. Passing a NULL pointer
    instead of a color will make the RImage be blended with the default color
    of the WINGs widgets: '#aeaaae' making it suitable to be assigned to any
    WINGs widget.


To make your existing code work as before all you need to do is to rename
the following functions:

   - WMSetApplicationIconImage()  --> WMSetApplicationIconPixmap()
   - WMGetApplicationIconImage()  --> WMGetApplicationIconPixmap()
   - WMSetWindowMiniwindowImage() --> WMSetWindowMiniwindowPixmap()

But if you want to take advantage of the new abilities to show alpha
blended images you need to start using the new functions.


